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Explore Ape Caves At Mt. St Helens National Volcanic Monument

At 8:32 Sunday morning, May 18, 1980, Mount St. Helens erupted and blew down or scorched 230 square miles of forest. Shaken by an earthquake measuring 5.1 on the Richter scale, the north face of this tall symmetrical mountain collapsed in a massive rock debris avalanche. In a few moments this slab of rock and ice slammed into Spirit Lake, crossed a ridge 1,300 feet high, and roared 14 miles down the Toutle River.

The eruption is considered to be the deadliest and most economically destructive volcanic event in the history of the United States.
In 1982 the President and Congress created the 110,000-acre National Volcanic Monument for research, recreation, and education. Inside the Monument, the environment is left to respond naturally to the disturbance.

Mount St Helens National Volcanic Monument is within the Gifford Pinchot National Forest. Numerous viewpoints and miles of trails have been created for you to explore by car and foot. During the summer Forest Interpreters lead a wide range of activities, from short walks to amphitheater presentations, to help you understand and enjoy this area.
The Gifford Pinchot National Forest offers lot's of recreational opportunities : camping, hiking, backpacking, mountain biking, climbing and caving.

But most people are attracted to this area by Ape Caves - a lava tube formed when the surface of a lava flow cooled and hardened.

About 2,000 years ago lava poured down the southern flank of Mount St. Helens in streams. As the lava flowed the outer edges of the lava stream cooled forming a hardened crust which insulated the molten lava beneath. This allowed the lava to remain hot and fluid encased in this “lava tube” and continued flowing months during the eruption. The end result was the creation of this spectacular 13,042 long lava tube.

It is the longest lava tube ( 12,810 feet or 3.9 kilometers ) in the conterminous United States (similar tubes are found in Oregon, California, and Idaho).

There are two parts of Ape Caves : Low and Upper Caves.

The lower Ape Cave is approximately is .75 miles long and can be hiked down and back in an hour.

The upper Ape Cave is 1½-mile long and takes about 2½ hours to complete, returning on a surface trail. This section is more adventurous as cavers must climb over approximately 27 boulder piles and scale an 8-foot high lava fall. The boulder piles formed after the eruption subsided and the fluid lava drained from the tube.

During the summer, a national monument interpretive naturalist leads tours through the lower part of the cave.

If you decide to explore the caves on your on, bring clothing layers: it’s 42˚ inside the lava tube. Wear rugged outer clothing, such as jeans, if you are going to crawl. Bring one headlamp and a spare flashlight per person; it is also advisable to rent a lantern at the Ape’s Headquarters ($5) - their lanterns have a wire mesh that protects the mantles, rather than glass, which could shatter in the cave. Wear protective gloves if you’re doing the Upper Cave. Camera lenses will fog over as you approach exits and vents. It takes about four hours to fully explore the entire lava tube.

After you're done exploring the caves, stop by another nearby attraction - Trail of Two Forests.

Set out on the nature trail, which provides illustrated panels to explain how this forest was transformed. A short distance up the boardwalk, check out the Crawl - a tunnel formed by a tree entombed by the lava flow.

The cave is open year round. It's about 3 hour dive from Seattle. National Forest Pass is required to park in the area.

No matter what season it is outside, you can always find something to do in the area !

In winter, this area is famous for snowmobiling, cross country skiing, and snowshoeing.